Agrin-like molecules in motor neurons.

According to the agrin hypothesis molecules that mediate the nerve-induced aggregation of acetylcholine receptors and acetylcholinesterase on developing and regenerating skeletal muscle fibers are similar or identical to agrin, a protein extracted from the electric organ of marine rays. Here we present evidence that agrin is highly concentrated in the cell bodies of motor neurons and is transported to axon terminals which is consistent with the agrin hypothesis.